1. Field of the Invention
The present invention relates to a molding die for multicolored molding that combines and integrates different resins, a molding method of a multicolored molded piece, and a multicolored molded piece.
2. Description of the Related Art
In general, double molding represents the following technology. Two different types of resin materials are used, an optical element and its adjacent member such as a frame member of the optical element are molded, and the optical element and the adjacent member are integrated. For example, Japanese Patent No. 3820137 discloses an example of this double molding. In Japanese Patent No. 3820137, a primary molding die used for performing primary molding with respect to the optical member and a secondary molding die for performing secondary molding with respect to the adjacent member are arranged. It should be noted that a movable die for the primary molding and a movable die for the secondary molding are used in common. Further, the optical member is primary molded in a cavity configured between a first fixed die and the movable die for the primary molding. Then, the first fixed die and the movable die are opened. At this time, an optical functional surface of the optical element remains being fitted in the movable die, and the optical element is held in the movable die. Then, in the secondary molding, the movable die holding this optical element is combined with a second fixed die for the secondary molding. Furthermore, the adjacent member is subjected to the secondary molding between the second fixed die and the movable die for the secondary molding. As described above, Japanese Patent No. 3820137 discloses the method for obtaining a double-molded piece of the optical element and the adjacent member.
Moreover, Jpn. Pat. Appln. KOKAI Publication No. 2004-1424 discloses the following contents. A first molded portion is molded in primary molding. In secondary molding, a secondary molding cavity is constituted of a first molded portion and a secondary molding die member. The secondary molding cavity is filled with a secondary molding molten resin. At this time, a surface of the first molded portion is molten by heat of the molten resin. Additionally, at the time of molding a double-molded piece, joining interface portions of the first molded portion and the secondary molding die member are bonded to each other.